An unexpected spy
by Blueflaregirl
Summary: Olivia a girl with a mysterious past show up at True cross. She seems just like the others...But is she really? Or is she there for another reason? She if being forced to help with some plot involving Yukio which could turn out pretty bad. Yukio X OC
1. Chapter 1

Hey this is my first fanfiction on here. I hope you enjoy it also I'm sorry if my grammar isn't good.

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Olivia grinned happily as she walked down the halls. She never thought she would get to go true cross. She then remember the reason and sighed. She then moved her blond hair out of her eyes and looked ahead of her with her dark blue almost like a black eyes. They thought of why she was here made her depressed because of wha-

_Smack!_

"Ow ow ow!"she said as she fell to the ground."I'm sorry wasn't looking where I was going"she said getting up. When she say who it was she breathed in deeply. She hadn't expected to meet him just yet. She had hoped she could have thought of an introduction and everything to say to him during cram school.

"It's alright but you should really pay attention"Rin said. He hadn't seen her before she had bumped into him. He looked at her and held out his hand. When Olivia took his hand he pulled her up.

Olivia sighed and looked at him"I'm Olivia Nakamura. SOrry about bumping into you like that"she said and held out her hand. She already knew his name but Rin didn't know and it would be best if he didn't suspect her yet. If she blew her cover she would be punished by her boss. She tried her best not to seem a bit sad.

Rin looked at her hand and then shook it."my name's Rin Okumura and it's alright as long as you don't make a habit of crashing into people"he said. He looked at her for a moment and frowned slightly. He noticed something was bugging her but he didn't know why.

Olivia looked back at him"is something wrong?she asked slightly concerned. She smiled at him"I think I should go. I got..uh...after school tutor help"she said nervously and quickly grabbed her bag and ran off.

Rin watched as she ran off in confusion. WHatever she didn't want to share must be pretty bad. He shrugged and went on his way to cram school.

* * *

Olivia got to the Cram school classroom with plenty of time to spare. She knew when Rin walked in she would have to seem surprised. She heard someone turn the doorknob of the door to the classroom and glance over at it.

Rin walked in and looked around the class for a moment. He stared at Olivia."YOU! what are you doing here?!"he exclaimed surprised. He hadn't expected to see her here when it was the middle of the school year.

"what are YOU doing here?"Olivia asked in a surprised tone. She hadn't expected him to react so loudly so some of the surprise in her voice was genuine. She heard someone sigh and bet most of the class was rolling their eyes.

"I go to the cram school of course. I am mainly wondering why you would be here when it's the middle of the school year!"he said still standing in front of the class when Yukio came in.

"Rin calm down and sit down already. Class has started"He said fixing his glass and glared at him. He went to his desk and waited until Rin sat down until he spoke."well as I'm sure you must have noticed we have a new student. WHy don't you introduce yourself?"he said with a smile at Olivia.

Olivia sighed and smiled. She stood up and introduced herself. Then she sat back down and got out the text-book she had gotten for this class. She wasn't one bit surprised that Yukio, who was the same age as everyone there, was their teacher. She had been informed of this already after all. When Yukio started teaching she looked at Rin who had sat next to her. He didn't seem very interested in the class at all which bothered her because she didn't understand why someone would go here saying that they are motivated and everything but act like this in class. She scowled and put her attention back on Rin's twin Yukio for the rest of class.


	2. Chapter 2

I'm posting this early because i'm going to be away the whole weekend. Sorry for the shortness I had wanted to do more but I don't have the time this weekend.

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When class ended Olivia got up from her seat and took out a piece of paper that contained the address of the dorm she would stay at. Her boss, more like owner, had written it down for her. He had mentioned that she would be surprised at where it was. She moved her hair behind her ear and looked up. she jumped slightly when she sat Rin was standing in front of her looking at the paper.

Rin frowned"why does that paper have the address of mine and yukio's dorm?"he said suspicious. He had already knew something was up with this girl but this just made him wonder even more.

Olivia looked at him a little shocked"wait...I thou-"she said interrupted by Yukio poking his head in and walking towards them.

"oh ya I forgot to tell Rin."Yukio said laughing lightly for a moment."Rin, Olivia is here to look after you when I'm not around. So she'll be staying at our dorm for a bit. Also I was informed she's had been informed of your...condition"he explained.

Olivia stared at Yukio for a moment. _He's actually...kind of...cute_. She sighed after Yukio spoke hiding the shock because she had not been informed she would be staying at the dorm."ya...that's right"she lied. She was actually here to watch Yukio. Her 'boss' had told her to watch him closely for any signs that he was a demon. She had other business to attend to here too.

Rin glared at Olivia"so you knew who I was the whole time?"he said angrily."why did you act shocked when I came in the class than? You already knew I was in the cram school didn't you?"he asked.

"well I..."she said and looked at the clock. Her eyes widened"crap! I REALLY need to go!"she exclaimed. She was going to be late for checking with her boss to let him know she got here successfully She also knew he was going to lecture her or mention what he is going to do if she didn't listen to him.

Rin and Yukio at her puzzled but moved so she could go."make sure not to get back to late. I have a mission at 8"Yukio stated as Olivia quickly jogged out of the room. He wondered what was up with her. When he looked at Olivia for the last second he noticed she had pointed ears like Rin."hmmm...hey Rin be careful around her. She seems a bit...odd"he said and started walking out with Rin.

"you tell me. When I first met her she seemed pretty sad even though she may have smiled and she acts really weird like just now"he said as he followed his brother.

* * *

When Olivia made it to the office she was only a few seconds from being late. She sighed in relief and opened the door"i'm here. Sorry for being almost late."she said and slowly sat down in the seat in front of his desk. She wondered what he would say. She didn't know what to expect sometimes other than the threat.

Mephisto turned his seat so he was facing Olivia"took you long enough."he said and smiled."remember if I can't rely on you I'll have to send you back to gehenna...and you don't want that do you?"he said grinning.

Olivia frowned"I know I know..."she mumbled looking down slightly."I'll do my best...if I go back there...my dad would kill me or worse."she mumbled to herself. She remembered how her dad had locked her away for nearly her whole life. He would torture her and blame her for ruining his life. He would always remind her of her brother's death as much as he could. She looked up and glared at Mephisto.

"anyways if you stay away any longer they'll get suspicious Mephisto said and shooed her."make sure you watch Yukio very closely when he's around and Rin too of course"he said.

Olivia glared at him intently for a few seconds and got up."I hate you but I'll do what you tell me"she said while she left the room. She didn't like the idea of lying straight to someone face about something so big but if she didn't she wouldn't ever get to live an real life. She would never get to stare at the sunset or look at the flowers. She wouldn't be able to grow to love anyone either. She would die alone in a dark room by the hand of her father.


	3. Chapter 3

When she had gotten back it was pretty late. She had gotten so badly lost trying to find the dorms she had to ask for directions. As she entered the building she saw her bags and picked them up. She saw Rin turn at the end of the hallway which was marked 'cafeteria'. She heard he was an excellent cook so she guessed he was going to cook something.

Olivia decided she would find the closest room and put her stuff in so she could see what he was up too. By the time she found a room suitable for living in she guessed that he would be finishing up. She sighed and hurried anyways to see if he was still possibly cooking dinner. When she got there the smell of the food cooking was irresistible. She couldn't help but find herself standing next to him looking at the food with a sparkle in her eyes."that smells and looks wonderful"she commented.

Rin hadn't heard Olivia walk in next to him so when she spoke he jumped back slightly, almost spilling what he was making."t-thanks"he said not calming himself after the shock of her surprising him like that."it's suppose to be tomorrow's lunch. You already missed dinner but the left overs are in the fridge...I saved them just in case you were hungry"he stated and got back to cooking.

Olivia nodded"alright and thanks Rin. That's a pretty nice gesture from a delinquent"she said and went to go get her dinner. What she hadn't expected was Rin exclaiming that he 'was not a delinquent'. She laughed anyways and just heated the heal up in the microwave."I was just messing with you. No need to take it so seriously"she said looking at him. She could tell Rin had moments where he didn't mind her but more of those moments were him being pissed at her jokes or just anything. At least so far.

"anyways i'll be out of your hair after my meal is done heating up. to bad though that I didn't get to try your dinner. Looks like it was wonderful when it was right from the pan, oven, or where ever"she explained. Not long after the microwave gave a sharp beeping sound that someone could easily hear all the way down the hall. She grabbed the plate of food and walked out of the kitchen.

Rin didn't know what was up with that girl. She seemed to have no sense of humor. Her calling him a delinquent was NOT funny. He just continued to coo the meal that he knew would go un-noticed by the girl at school. He didn't care that much anyways. He had his eyes set on Sheimi anyways.

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The next day Olivia woke up with the sun shining brightly right in her eyes."I hate sunlight"she mumbled and covered her head with the blanket. She never liked bright lights and the sun was the brightest you could find. After a while when she was just about to slip back into sleep, someone had decided to knock on her door like someone was dying. She tried her best to ignore it but it got louder."Fine i'm up! Now stop bagging on my door!"she yelled and thankfully the pounding stopped.

She got dressed in the school uniform sluggishly. She was still extremely tired and the rude awakening she had gotten didn't help out either. When she was done getting ready she hadn't looked at the clock once and didn't realize how late she really was was class. She walked down the halls like she had the luxury of time. When she finally DID see a class she flipped the hell out."Holy crap!"she exclaimed. she had missed her first 3 classes of the day and worse now the teachers would think she was a delinquent. She groaned and started to quickly walk to school. There was no use. She was already late so just being a little more late wouldn't effect how much trouble she had already gotten in.

By the time she got there she was just in time for 4th period and a lecture on how attendance was important by the teacher. She had apologized and said it wouldn't happen again and sat down. She looked at Yukio and wasn't glad to see that he looked quite disappointed in her. She didn't blame him since he was a goody-goody and a nerd plus he must be thinking about something like 'how can she guard my brother if she can't even wake up on time for school'.


	4. Chapter 4

Hello guys :D sorry about the wait. I hope you like this Chapter.

I do NOT own Blue Exorcist or any of their Character only my OC

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Once class had ended Olivia didn't know what to say to Yukio to make him less disappointed in her. She really wished she hadn't slept in on accident like she had. She sighed and just continued with her day. The rest of the day was really boring and tedious. She also had a hard paying attention but she was able to force herself too. When it came time for her to go to the cram school she wasn't having as hard of a time paying attention.

When class started Yukio started explaining that he would be passing out forms for the study camp for the exam to officially become a page. When he was done telling them that he went back to teaching the lesson. It was a pretty simple class for Olivia since she was good at remembering facts. The hardest part though was trying to remember the name of something if she had never heard of it before, that is unless it was an interesting plant.  
When Class ended Yukio handed out a piece of paper that told them to check off if they were going to the study camp, and if not, why. It also said to state the Meister you were aiming towards getting.

Olivia looked over the paper and started thinking about what she wanted to do. She didn't like the idea of being a tamer because even though they were rare all they did was let their familiars do all the work. If she were to become a tamer she would make sure that she would choose another meister also so she could have two lines of attack/defense and not feel useless. She liked the idea of Night or Dragoon because she liked the idea of being in the action. An Aria was too defenseless for her liking even though she considered them one of the stronger types of meister because if you know they death verse you could take a high level demon down in a few sentences, but they also didn't use weapons and the demons always tend to focus on them when they chant

Olivia decided she would try for Knight, Dragoon, Knight and Tamer, or Dragoon and Tamer. It seemed like a great combination to her since they were really the strongest in her opinion. She smiled and decided she would wait to see if she COULD be a Tamer before choosing.  
Olivia waited in her seat a bit sleepily because the new teacher for magic circles was taking his time arriving to the classroom. It wouldn't be much longer before she knew if she had the potential of being a Tamer, since she knew their next teacher's lesson was to see who would be the rare few to be able to become a Tamer.

When the teacher finally got there he told everyone to push the tables and chairs to the edge of the classroom. When they finished what he told them, he started to draw a summoning circle. After a while he finished and summoned a Ghoul. Olivia stared at it in awe. It was such a big one and it was a high level demon too.

The teacher passed out small slips of paper to each student. He explained to them how it works and what to do if something went wrong. He also explained a demon with only folow a persons orders only if they heart doesn't waver. He instucted them to but a drop of blood on the paper and try to summon a demon.

Olivia observed of Izumo was able to summon two white foxes and the Shiemi was able to summon a baby greenman. She noticed Rin didn't even tr to summon one. She swallowed and thought up something to say for summoning a demon. She dripped a drop of blood on the paper and started speaking."oh lord of fire...please grant my request"She whispered in a comanding voice. When a demon showed up before her she started to stare. She hadn't expected it to work so well. It was about two and a half feet tall and it was on fire. Red fire of coure. It looked a lot like a dog too. Everyone stared at the dog in awe and the teacher spoke up."good job Ms. Nakamura. You summon a baby hellhound. It's a mid-level demon and they can be quite...feirce at times. They also frow to a massive size."he explained.

Olivia smiled at the dog and petted it. The flames didn't seem to effect her so she was glad. She guessed they didn't because she was the dog's master so it had to refrain from harming her."it's so cute"she said but wished he was slightly smaller than he was. She shurgged."i'm not getting rid of you alright? but i'm expecting you to stay at the dorm and not destroy anything"she explain to the hellhound.

Once classes for cram school had ended Olivia met up with Rin to go back to the dorm. Rin glanced at the hellhound a lot on the way to the dorm. When they got there Olivia pouted and looked at Rin."is there something wrong with my familiar?"she asked with a raised eyebrow. When Rin shook his head she sighed."than why were you staring at him?"she asked.

Rin rolled his eyes"I was just staring because he/she looks like a pretty cool familiar. Like seriously, no one would wanna mess with you with that guys. Just look at him. He's a big dog with flames."he replied.

Olivia smiled"thanks. I think he's just cute though. I can protect myself...well most of the time. Plus even if I get hurt, I should be able to handle most of the pain. I didn't exactly live a normal childhood"she said with a small laugh."where I lived you had to toughen up to survive"she explained hoping he wouldn't get suspicous."also, I'm sorry if I pissed you off before. Let get along alright?"she said with a wide smile and stuck out her hand.

Rin blinked a little bit survived by the fast change of subject. He shrugged and shook her hand."alright"he said with a wide and goofy smile.

Olivia heard someone cough and jumped. She blushed in embarrasment for an odd moment."oh, Hey Yukio"she said with a smiled. She was kind of glad that he poped up."I wanted to say sorry about being late. I'm not used to sleeping long so my body took the chance it had to get a good rest for once"she explained.

Yukio nodded in understanding."next time I suggest you not ignore the pounding at your door. Rin was late to class because he didn't want you to be extremely late or miss your first day of school"he explained."anyways, congradulations on summoning a demon. Tamers are rare to come by. So what meister are you choosing?"he asked.

Olivia stared at Rin when Yukio said that he had been the once that woke her up. She muttered a thank you to Rin with a smile."oh, I was actually thinking of possibly choosing two Meisters. Tamer and Dragoon preferably."she explained. She was glad when Yukio nodded and told her to just remember to wright it down on the paper."already did"she replied.

Yukio Nodded glad she remembered."well that's good. Oh Olivia, I have a mission in about an hour so I have to prepare for it. You'll have to watch Rin for a few hours. Make sure he doesn't get out"he said and glared at Rin. He knew his brother would try to follow him.

Olivia nodded"alright. I'll make sure he doesn't get out."she said with a smile.

* * *

Olivia was glad that Rin hadn't even tried to run off on her watch. When Yukio got back he was pleased which made her happy. She didn't know why but she cared a lot about what he thought about her."well i'm going to bed now that you're back."she explained and left for her room down the hall. She did a little bit of studying before going to bed, cuddled next to her new pet.


	5. Chapter 5

Hey guys. I'm back with more. I hope to be writing a lot over the summer for this fan fiction. I have a big surprise coming your way. Not sure when i'll throw it at you but I can tell you it's a pretty big surprise.

I DO NOT own Blue Exorcist only my OC character.

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It had been a week and nothing much really happened. They went to the study camp with most likely the most work they would ever do within a week the worst it had gotten was Shima trying to peek on the girls. Now it was the last day of the camp and Bon HAD to get in a fight with Izumo. Something about dissing Arias.

Olivia was sitting next to Izumo with the boron in her lap just like the rest of them. She felt like snapping at the two but was stopped short by Yukio speaking up."I have to go a mission so when I leave i'll be locking the doors because of the demon incident"he explained and left the room. she felt slightly angry at him because he was the one that choose this punishment for everyone.

Soon a commotion started up next to her between Izumo and Bon. Rin had spoke up, telling them to stop fighting with him in the middle. She decided this was the best time to say something too."Shut the hell up already Izumo and Bon. I'm tired of you guys fighting!"she exclaimed which got their attention."we have to work together if we want to become exorcist so settle your stupid argument already. Yes, Arias can be defenseless but they are one of the more useful Meisters as they can kill a demons with merely a few words."she explained.

Just as Olivia finished talking the light shut off. She heard Rin exclaim from pain while she was slightly blinded. When her vision focused she realized why. Rin had jumped up and hit his toes with the rock like demon. She chuckled and got up carefully without hurting herself like he had. She listened as everyone muttered about 'did he turn off the lights on his way out' and 'maybe it was a power outage'. She was glad someone had pointed out that it wasn't a power outage because of the lights still shining outside.

Shima got up and started walking towards the door."I'm going outside"He said. Olivia heard Konekomaru warn Shima to be careful. She knew he would be fine but she hoped nothing was going to go wrong. She had an odd feeling in the pit of her stomach like something was wrong. Shima laughed at the boys warning and continued towards the door"I love stuff like this, it's a real test of courage"he said and opened the door"there's nothing here, see". Shima looked at the door, blinked, and closed it."my eyes must be playing tricks on me, either that or we got a dem-ahhh!"he said cut off my a giant fist crashing through the door.

"holy crap!"Olivia exclaimed in shock, along with a few other people who just yelled. When the Ghoul started crawling through the door, Olivia started to calm down slightly but was having a hard time focusing on what she should do. She heard a few people start to speak up about 'the Ghoul came back' and 'what about the demon warding charm?!". Olivia thought she had an idea of how it got in but she didn't have time to just sit there and do nothing.

Olivias' eyes widened at the Ghouls second head seemed to grow for a moment, until it looked like bursting. Unfortunately for her and everyone else it did burst. At least half of the people in the room raised there arms to block whatever it had sprayed. It was Miasma. She didn't waste her time sitting around wondering what it was. She quickly summoned her familiar, which she named flare ironically, so she could help out in the fight. When Shiemi used her familiar to create a wall between the Ghoul and everyone she started to calm down for a moment. Just when she thought she could relax the Ghoul broke in two and started to brake the roots, that Shiemi's familiar had created, with their brute strength.

Next thing she knew the rest of the class except for Rin and herself started to get weak. She growled in frustration but was glad a story about it not effecting them would seem more plausible since it was two people instead of one that wasn't effected."Rin, if you leave to go of on your own i'll chase you down. You got that?! no exorcist fights alone and besides I promised them I would watch you"she said sensing Rin's plan on leaving. She yelled at him when he still kept on going."dammit!"she exclaimed and followed after him. She was glad that she got out of the room after the second Ghoul went after Rin. She didn't want to get in the way of a rampaging Ghoul.

Olivia knew it she didn't hurry up Rin would use his flames on the Ghoul would not be a good thing. She calmed down and starting focusing on her speed. It took her a moment to get enough focus to pull it off but she was finally able to pick up her speed so rapidly, someone would have thought she teleported. The speed up she did only lasted a moment but it allowed her to get in front of the Ghoul and right behind Rin."Rin! Don't do anything stupid. You know what will happen if you use it. Use your head...never mind don't use your head. Use a pole or something just not you sword."she said and reworded it knowing he would actually use his head.

Rin didn't care what Olivia said about not using his flames. He knew if he didn't, the Ghoul would get away and harm someone."sorry can't do that"he said when he got to the room. He instantly pulled his sword despite the look of distaste on Olivia's face. He knew she would chew him out later for it but he had no choice.

Olivia felt like she was about to burst from the anger of Rin disobeying her."dammit Rin!"she said when she took notice of a man in the shadows. He soon stepped out, revealing himself to be Igor, their teacher for magical circles.


End file.
